1. Field of the Invention
The invention relates to a belt band conveyor having an endless conveyor belt band, preferably motor-driven, that is guided over deflection friction rollers and/or over drive friction rollers, preferably motor-driven, with its lower belt, for deflecting and/or driving the conveyor belt band.
The rollers each comprise a shaft that extends in a longitudinal direction, which shaft has an outside circumference contour, wherein at least three roller segments are mounted on the shaft, which segments are disposed axially adjacent, in each instance, in the longitudinal direction, at an axial distance from one another, and wherein each roller segment of the roller segments is mounted so as to rotate about an axis of rotation that extends axially in the longitudinal direction, and has an inside circumference contour, and wherein each roller segment of the roller segments has a friction surface that runs around the axis of rotation, in the circumference direction, on its radial outside circumference, and wherein each roller segment of the roller segments engages on the lower belt of the conveyor belt band exclusively with friction fit, by way of the respective friction surface.
2. Description of the Related Art
Belt conveyors essentially consist of a drive drum and a deflection drum. The materials are the shaft or axle with pipe mantle and roller inserts such as fixed inserts or also bearing housings. The drive drum is generally provided with a lining composed of a skid-resistant belt material, or also with a rubber coating or similar material. The coating ensures a greater friction factor and thereby greater skid resistance between the drive drum and the belt. Furthermore, the skid resistance serves to reduce the tension of the belt, and this tension reduction can lead to a longer useful lifetime of the belt material.
The deflection drum and drive drum are similar in structure at the manufacturers, and have been complicated, in unchanged manner, for many years. For example, the drum of straight belt conveyors or of straight belts must be re-worked by means of a lathe tool, for example, in order to produce a certain convexity. The convexity is necessary to prevent the belt from slipping off at the side. Lathing off or grinding off of the drum coating, in order to achieve the convexity, is also complicated. In simple application cases, it is also sufficient, for cost reasons, to increase the height of the drum at the center, by mean of a skid-resistant lining, in order to hold the belt in the center, using this method.
Deflection drums and drive drums of curved belts are particularly complicated. Curved belts require conical rollers, because the belt runs faster on the outside than on the inside, and this difference must be balanced out using the conical roller. Frequently, common drive shafts or deflection shafts have a plastic cast around them conically. The roller, which has been conically cast or conically recast in this manner, is then ground off, and then the ends are re-worked once again, with chip removal.
All the embodiments have in common that they are very complicated in terms of production. Often, the drum already makes up a significant percentage of the production costs of a belt conveyor.
Belt band conveyors having the characteristics mentioned initially have become known, for example, from DE 198 05 204 A1 and DE 10 2004 012 344 A1. In the case of these belt band conveyors, it can be provided that the running rollers and/or the deflection rollers are formed, in each instance, by a roller axle or roller mounted on the side cheek of the belt band conveyor, axially adjacent to and independent of one another, preferably freely rotatable. In the exemplary embodiments described there, drive of the conveyor belts takes place by means of a drive unit disposed below the lower belt run, by means of a motor-driven friction wheel, which interacts with the lower belt run with friction fit. According to DE 10 2004 012 344, however, the drive of the conveyor belts can also take place directly by way of the running rollers and/or by way of the deflection rollers, with friction fit or force fit. Furthermore, drive can also take place with shape fit there. For this purpose, engagement elements can be provided on the drive side, which elements interact with engagement elements on the power take-off side, which in turn are attached to the conveyor belt. These designs are also relatively complicated and correspondingly expensive. Furthermore, transfer of force and moment by the roller segments that can rotate about the shaft independent of one another is not possible, or possible only insufficiently.